Channel defining fuel nozzle of combustion system

ABSTRACT

A combustion system is provided and includes an annular body defining a combustion zone and a fuel nozzle. The fuel nozzle includes a tubular element having a hollow interior and is disposable such that the hollow interior fluidly communicates with the combustion zone. The tubular element includes wall portions defining a channel disposable for fluid communication with at least one of the hollow interior and the combustion zone. The defined channel is pressurizable with coolant at a pressure exceeding that of the combustion zone.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to a combustion system and, more particularly, to a combustion system including fuel nozzle wall portions defining a channel.

In gas turbine engines, a compressor compresses inlet air and outputs the compressed inlet air to a combustor. Within the combustor, the compressed inlet air is mixed with fuel and combusted to produce a high temperature and high pressure working fluid. The working fluid is directed into a turbine section where it is expanded to drive operations of the compressor and a generator. The high temperatures and high pressures generated within the combustor can at times lead to flash back incidences or to flame holding. In such cases, the combustion of the compressed inlet air and fuel occurs too close to the combustor hardware and can lead to thermal damage of the hardware if the failure is not corrected or otherwise stopped from occurring.

Typically, devices for correcting or otherwise stopping flash back incidences and flame holding are fuel nozzle fuses. These fuses are installed in fuel nozzles of the combustor of a gas turbine engine and are configured to activate when flash back incidences or flame holding occurs. When activated, the fuses may shut down the combustion and thus act as an identifier that a failure has occurred.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the invention, a combustion system is provided and includes an annular body defining a combustion zone and a fuel nozzle. The fuel nozzle includes a tubular element having a hollow interior and is disposable such that the hollow interior fluidly communicates with the combustion zone. The tubular element includes wall portions defining a channel disposable for fluid communication with at least one of the hollow interior and the combustion zone. The defined channel is pressurizable with coolant at a pressure exceeding that of the combustion zone.

According to another aspect of the invention, a combustion system is provided and includes an annular body defining a main combustion zone and a downstream combustion zone downstream from the main combustion zone and a fuel nozzle. The fuel nozzle includes a tubular element having a hollow interior and is disposable such that the hollow interior fluidly communicates with the downstream combustion zone. The tubular element includes wall portions defining a channel disposable for fluid communication with the downstream combustion zone. The defined channel is pressurizable with coolant at a pressure exceeding that of the downstream combustion zone.

According to yet another aspect of the invention, a combustion system is provided and includes an annular body defining a combustion zone and a fuel nozzle. The fuel nozzle includes a tubular element having a hollow interior and is disposable such that the hollow interior fluidly communicates with an upstream-most portion of the combustion zone. The tubular element includes wall portions defining a channel disposable for fluid communication with at least one of the hollow interior and the combustion zone. The defined channel is pressurizable with coolant at a pressure exceeding that of the combustion zone and the hollow interior.

These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic illustration of a gas turbine engine in accordance with embodiments;

FIG. 2 is a side schematic view of a combustion system of the gas turbine engine of FIG. 1, which includes a fuel nozzle at a downstream combustion zone in accordance with embodiments; and

FIG. 3 is a side schematic view of a combustion system of the gas turbine engine of FIG. 1, which includes a fuel nozzle at an upstream-most portion of a combustion zone in accordance with embodiments.

The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1-3, a gas turbine engine 1 is provided and includes a compressor 2, a combustor 3, a transition piece 4 and a turbine section 5. The combustor 3 includes an annular body 30 formed to define a combustion zone 301 having a main combustion zone 302, an upstream-most portion 303 of the main combustion zone 302 and a downstream combustion zone 304 defined downstream from the main combustion zone 302. The compressor 2 compresses inlet air and outputs the compressed inlet air to circuits 6 and 7. Circuit 6 provides for a mixing of the compressed air with fuel and an injection of the resultant fuel/air mixture into a head end 31 of the combustor 3 and proximate to the upstream-most portion 303 of the main combustion zone 302. Circuit 7 provides for a mixing of the compressed air with additional fuel and an injection of the resultant fuel/air mixture into a downstream section 32 of the combustor 3 or to the transition piece 4 and proximate to the downstream combustion zone 304.

The fuel/air mixtures are combusted within the combustor 3 to produce a working fluid of high temperature and high pressure combustion products. The working fluid is directed into the turbine section 5 via the transition zone 4 and is expanded within the turbine section 5 to generate work. The expansion of the working fluid in the turbine section 5 causes a rotor 8, which extends through the compressor 2, the turbine section 5 and a generator 9, to rotate and such rotation drives operations of the compressor 2 and the generator 9.

As described below, a combustion system 10 is provided for use with the gas turbine engine 1 and includes the annular body 30 and a fuel nozzle 40 (see FIGS. 2 and 3). The fuel nozzle 40 includes a tubular element 50 having a hollow interior 500 and is disposable on the annular body 30 such that the hollow interior 500 fluidly communicates with the combustion zone 301. The tubular element 50 includes wall portions 60 that define a channel 70. The channel 70 is disposable for fluid communication with at least one of the hollow interior 500 and the combustion zone 301. The channel 70 is pressurizable with coolant 71 at a first pressure P1. In accordance with certain embodiments, the first pressure P1 exceeds a second pressure P2 of the hollow interior 500 and the second pressure P2 of the hollow interior 500 exceeds a third pressure P3 of the combustion zone 301.

In greater detail, as shown in FIG. 2, the combustion system 10 includes the annular body 30, which defines the main combustion zone 302 with a longitudinal axis A1 and the downstream combustion zone 304 in a position defined fluidly downstream from the main combustion zone 302, and the fuel nozzle 40. As shown, the fuel nozzle 40 may be provided as a late lean injection (LLI) fuel nozzle 400 and the annular body 30 may include a secondary annular body 33 and a tertiary annular body 35. The secondary annular body 33 may be disposed about the annular body 30 and the tertiary annular body 35 may be disposed about the secondary annular body 33. In this case, the fuel nozzle 40 includes a fuel nozzle body 41, which is disposed proximate to an aft end of the secondary annular body 33, and which traverses the secondary annular body 33 such that the tubular element 50 extends from the tertiary annular body 35 to the annular body 30 and a longitudinal axis A2 of the tubular element 50 is oriented transversely with respect to the longitudinal axis A1 of the annular body 30.

With the tubular element 50 having the hollow interior 500 and the fuel nozzle 40 being disposed proximate to the aft end of the secondary annular body 33, the hollow interior 500 is fluidly communicative with the downstream combustion zone 304. As such, by way of the circuit 7 and fuel tube 34, the fuel/air mixture can be injected into the downstream combustion zone 304 to thereby increase temperatures of the working fluid within the combustor 3 and the transition piece 4. This increase in temperatures can lead to increased output of the generator 9.

The increase in temperatures can also lead to an increased likelihood of flash back incidences and in turn to potential damage of the combustion system 10. Examples of such damage may include thermal damage to the annular body 30 around the fuel nozzle 40. As shown in FIG. 2, however, the tubular element 50 includes the above-noted wall portions 60 that define at least one or more channels 70. The at least one or more channels 70 may be disposable for fluid communication with an interior of the tertiary annular body 35 and the downstream combustion zone 304. In this way, the coolant 71 may be supplied to the at least one or more channels 70 by the tertiary annular body 35 at the first pressure P1, which exceeds the second pressure P2 of the hollow interior 500, which in turn exceeds the third pressure of the downstream combustion zone 304.

Each one of the at least one or more of the channels 70 may include a first portion 701 and a second portion 702. The first portion 701 is oriented transversely with respect to the longitudinal axis A2 of the tubular element 50 and the second portion 702 is oriented along the longitudinal axis A2 of the tubular element 50. Thus, a pressurized flow of the coolant 71 proceeds along the first portion 701 from the tertiary annular body 35 in a radially inward direction with respect to the longitudinal axis A2 toward the hollow interior 500. The pressurized flow of the coolant 71 then proceeds along the second portion 702 in a radially inward direction with respect to the longitudinal axis A1 and toward the downstream combustion zone 304. In so doing, the coolant 71 removes heat from the local portions of the annular body 30 and the fuel nozzle 40.

In accordance with embodiments, the second portions 702 of the at least one or more channels 70 may be located near regions of the wall portions 60 that are most likely to experience high temperatures or heat due to flash back exposure. These regions may include fuses 80 having first fuse bodies 81. The first fuse bodies 81 may be thinned as compared to other regions of the wall portions 60 such that they melt before the other regions of the wall portions 60. Alternatively, the first fuse bodies 81 may be made of material that melts at a lower temperature than that of the other regions of the wall portion 60. In an event of a flash back incidence, the thinned or otherwise low melting point material of the first fuse bodies 81 melts and such melting results in an enlarged flow area of the at least one or more channels 70. This enlarged flow area permits an additional flow of coolant 71 and provides for a local source to push out the flash back incidence and prevent extensive hardware damage, as well as cause an increase in emissions that signals that a potential issue has occurred.

In accordance with embodiments and, as shown in FIG. 2, the at least one or more channels 70 may be provided as a single channel 70 or as a plurality of channels 70. In the latter case, the plurality of the channels 70 may be arrayed around the tubular element 50 in an annular or substantially circular array shape or in some other suitable array shape or formation.

As shown in FIG. 3, the combustion system 10 includes the annular body 30, which defines an end of the main combustion zone 302 with the longitudinal axis A1 and the upstream-most portion 303 of the main combustion zone 302, and the fuel nozzle 40. As shown, the fuel nozzle 40 may be provided upstream of a burner tube assembly 401, which surrounds the tubular element 50. With the tubular element 50 having the hollow interior 500 and the fuel nozzle 40 being disposed proximate to the upstream-most portion 303 of the main combustion zone 302, the hollow interior 500 is fluidly communicative with the upstream-most portion 303 of the main combustion zone 302. As such, the fuel/air mixture can be injected into the upstream-most portion 303 of the main combustion zone 302 by way of the circuit 6 in combustion operations.

As described above, such combustion operations can lead to flash back incidences and to damage of the combustion system 10 with examples of such damage including thermal damage to the annular body 30 around the fuel nozzle 40. As shown in FIG. 3, however, the tubular element 50 includes the above-noted wall portions 60 that define at least one or more channels 70. The at least one or more channels 70 may be disposable for fluid communication with an exterior of the burner tube 402 and at least one of the hollow interior 500 and the upstream-most portion 303 of the main combustion zone 302. As such, the coolant 71 may be supplied from the exterior of the burner tube 402 to the at least one or more channels 70 at the first pressure P1, which exceeds the second pressure P2 of the hollow interior 500, which in turn exceeds the third pressure P3 of the upstream-most portion 303 of the main combustion zone 302.

Each one of the at least one or more channels 70 may be oriented along the longitudinal axis A2 of the tubular element 50 and by extension along the longitudinal axis A1 of the main combustion zone 302. In accordance with embodiments, one of the at least one or more channels 70 may extend from an upstream portion 501 of the tubular element 50 and may terminate at a downstream end 502 of the tubular element 50. In accordance with alternative embodiments, one of the at least one or more channels 70 may extend from the upstream portion 501 of the tubular element 50 and may terminate proximate to the downstream end 502 of the tubular element 50. In accordance with still further alternative embodiments, the at least one or more channels 70 may include first channels 72, which extend from the upstream portion 501 of the tubular element 50 and terminate at the downstream end 502 of the tubular element 50, and second channels 73, which extend from the upstream portion 501 of the tubular element 50 and terminate proximate to the downstream end 502 of the tubular element 50.

The second channels 73 of the embodiments of FIG. 3 provide for film-cooling effects of local portions of the tubular element 50 and the annular body 30. It is to be understood that similar structures can be provided in the embodiments of FIG. 2 apart from the first fuse bodies 81. In such cases, as with the second channels 73 of FIG. 3, alternative embodiments of the second portions 702 of the at least one or more channels 70 of FIG. 2 can terminate proximate to the downstream end of the hollow interior 500 to provide for film-cooling effects of the local portions of the tubular element 50 and the annular body 30.

In accordance with embodiments, the first channels 72 and the second channels 73 may be located near regions of the wall portions 60 that are most likely to experience high temperatures or heat due to flash back exposure. These regions may include fuses 80 having second fuse bodies 82. The second fuse bodies 82 may be thinned as compared to other regions of the wall portions 60 such that they melt before the other regions of the wall portions 60. Alternatively, the second fuse bodies 82 may be made of material that melts at a lower temperature than that of the other regions of the wall portion 60. In an event of a flash back incidence, the thinned or otherwise low melting point material of the second fuse bodies 81 melts and such melting results in an enlarged flow area of the at least one or more channels 70. This enlarged flow area permits an additional flow of coolant 71 and provides for a local source to push out the flash back incidence and prevent extensive hardware damage, as well as cause an increase in emissions that signals that a potential issue has occurred.

Fuel nozzles for gas turbine engines have employed fuses that help prevent catastrophic damage in the event of a flash back. These fuses can degrade, however, and cause a false outage. With this in mind, fuel nozzles with micro-channels, such as those described above, can be used for cooling purposes instead of or in addition to fuses and still provide for the introduction of coolant at flame-holding locations as an emissions trigger.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

1. A combustion system, comprising: an annular body defining a combustion zone; and a fuel nozzle comprising a tubular element having a hollow interior and being disposable such that the hollow interior fluidly communicates with the combustion zone, the tubular element comprising wall portions defining a channel disposable for fluid communication with at least one of the hollow interior and the combustion zone, the defined channel being pressurizable with coolant at a pressure exceeding that of the combustion zone.
 2. The combustion system according to claim 1, wherein the pressure of the coolant exceeds that of the hollow interior with the hollow interior being pressurized at a pressure exceeding that of the combustion zone.
 3. The combustion system according to claim 1, wherein the annular body has a longitudinal axis and the tubular element has a longitudinal axis oriented transversely with respect to the longitudinal axis of the annular body.
 4. The combustion system according to claim 3, wherein the defined channel comprises: a first portion oriented transversely with respect to the longitudinal axis of the tubular element; and a second portion oriented along the longitudinal axis of the tubular element.
 5. The combustion system according to claim 1, wherein the defined channel is provided as a plurality of channels arrayed around the tubular element.
 6. The combustion system according to claim 1, wherein the annular body has a longitudinal axis and the tubular element has a longitudinal axis oriented along the longitudinal axis of the annular body.
 7. The combustion system according to claim 6, wherein the defined channel is oriented along the longitudinal axis of the tubular element.
 8. The combustion system according to claim 1, wherein the defined channel extends from an upstream portion of the tubular element and terminates at or proximate to a downstream end of the tubular element.
 9. The combustion system according to claim 1, wherein the defined channel is provided as a first channel and a second channel, the first channel extending from an upstream portion of the tubular element and terminating at a downstream end of the tubular element, and the second channel extending from the upstream portion of the tubular element and terminating proximate to the downstream end of the tubular element.
 10. The combustion system according to claim 1, wherein the wall portions comprise a flash back incidence fuse.
 11. A combustion system, comprising: an annular body defining a main combustion zone and a downstream combustion zone downstream from the main combustion zone; and a fuel nozzle comprising a tubular element having a hollow interior and being disposable such that the hollow interior fluidly communicates with the downstream combustion zone, the tubular element comprising wall portions defining a channel disposable for fluid communication with the downstream combustion zone, the defined channel being pressurizable with coolant at a pressure exceeding that of the downstream combustion zone.
 12. The combustion system according to claim 11, wherein the annular body has a longitudinal axis and the tubular element has a longitudinal axis oriented transversely with respect to the longitudinal axis of the annular body.
 13. The combustion system according to claim 12, wherein the defined channel comprises: a first portion oriented transversely with respect to the longitudinal axis of the tubular element; and a second portion oriented along the longitudinal axis of the tubular element.
 14. The combustion system according to claim 11, wherein the defined channel is provided as a plurality of channels arrayed around the tubular element.
 15. A combustion system, comprising: an annular body defining a combustion zone; and a fuel nozzle comprising a tubular element having a hollow interior and being disposable such that the hollow interior fluidly communicates with an upstream-most portion of the combustion zone, the tubular element comprising wall portions defining a channel disposable for fluid communication with at least one of the hollow interior and the combustion zone, the defined channel being pressurizable with coolant at a pressure exceeding that of the combustion zone and the hollow interior.
 16. The combustion system according to claim 15, wherein the annular body has a longitudinal axis and the tubular element has a longitudinal axis oriented along the longitudinal axis of the annular body.
 17. The combustion system according to claim 16, wherein the defined channel is oriented along the longitudinal axis of the tubular element.
 18. The combustion system according to claim 15, wherein the defined channel extends from an upstream portion of the tubular element and terminates at a downstream end of the tubular element.
 19. The combustion system according to claim 15, wherein the defined channel extends from an upstream portion of the tubular element and terminates proximate to a downstream end of the tubular element.
 20. The combustion system according to claim 15, wherein the defined channel is provided as a first channel and a second channel, the first channel extending from an upstream portion of the tubular element and terminating at a downstream end of the tubular element, and the second channel extending from the upstream portion of the tubular element and terminating proximate to the downstream end of the tubular element. 